The present inventions relate to a slurry for use in electrode formation and a production method thereof, and more specifically, a metal slurry for electrode formation wherein a spherical metal powder is used and which slurry is excellent in dispersion property.
Conventionally, as a method for electrode formation on electronic components, “screen printing method for thick-film electrode formation” has been widely used in which a high viscosity paste for electrode formation is prepared and printed on the electronic components through a screen. In the screen printing method, the electrode pattern is determined by the screen pattern, and accordingly different electrode patterns require respectively different screen patterns prepared. Consequently, the conventional screen printing method involves the problems that it is not only unfavorable in cost but also difficult to meet quickly the electrode patterns changing with the design innovation in electronic components.
For the purpose of solving the above mentioned problems, nowadays, there has been developed such an electrode forming method that uses “jet printing technique” (hereinafter, the printhead used in the jet printing technique will be referred to as “jet printhead”). A method and apparatus for such jet printing is disclosed in allowed, co-assigned, U.S. patent application, U.S. Ser. No. 09/445,670, entitled JETTING LAYERS OF POWDER AND THE FORMATION OF FINE POWDER BEDS THEREBY, in the names of inventors Emanuel M. Sachs et al., 35 U.S.C. 102(e) date Mar. 1, 2000, which was the U.S. National Phase of PCT/US98/12280, filed Jun. 12, 1998, and published on Dec. 17, 1998, the full disclosure of which is hereby fully incorporated by reference herein. In this method, the slurry for use in electrode formation (hereinafter, referred to as “metal slurry for electrode formation” or simply “slurry” as the case may be) is prepared, which slurry is printed on a substrate by use of the jet printhead. The nozzle arranged in the jet printhead is as small as 10 to 130 μm in diameter, and hence there cannot be used such a high viscosity slurry that causes nozzle clogging. Accordingly, the metal particle sizes in the slurry are made small for the purpose of regulating the slurry viscosity. Incidentally, in the present specification, a powder means an ensemble of particles; the term “powder” will be used for the case where the material concerned is judged to be suitably referred to as powder in view of its nature as an ensemble of particles, while the term “particle” will be used for the case where the material concerned is judged to be suitably referred to as particle in view of its nature as the units constituting the powder. Since the powder and the particle share the common constituent unit, sometimes there may be, needless to say, no substantial difference between those matters which are meant by these two terms. In other words, sometimes either of the terms “powder” and “particle” can be used.